Metallic card clothing

ABSTRACT

When combing yarn, and particularly synthetic yarn, the metallic card clothing wire has a short life. To extent the life of the card clothing wire, a hard layer selected from a group consisting of vanadium carbide, chromium carbide, tungsten carbide, molybdenum carbide, niobium carbide, tantalum carbide, titanium carbide, zirconium carbide, hafnium carbide and iron boride is difused onto the steel. This hard layer has a smooth working surface and a uniform thickness in the range of from about 8 to 20 microns.

United States Patent 1191 Arai et a1. Sept. 10, 1974 1 4] METALLIC CARD CLOTHING 2,872,348 2/1959 Eubank 117/130 R 3,387,338 6/1968 Kanai et a1 19/114 [75] Inventors: Ara; Masaywhl l 3,634,145 1/1972 1161mm 148/6.1l both of Nagoya, Japan 3,671,297 6/1972 Komatsu et a1. 117/130 R 1 AssigneeI fi z g Kgisha g FOREIGN PATENTS OR APPLICATIONS en yus agoya's apan 1,551,509 11/1968 France 19/114 [22] Filed: Mar. 6, 1972 2 A L N 231 949 Primary Examiner-Charles N. Lovell 1 pp 0 Attorney, Agent, or Firm-Holman & Stern [30] Forelgn Application Priority Data 57] ABSTRACT Mar. 9, 1971 Japan 46-12895 When combing yarn, and particularly synthetic yarn, 52 US. Cl 19/114, 29/183, 29/196, the metallic card clothing wire has a Short life- To 148/611, 143/315 tent the life of the card clothing wire, a hard layer se- 51 Int. Cl... D01g 15/84, B32b 15/04, B32b 15/18 lectedfrom a r p consisting of Yanadium carbide, [58] Field of Search 19/114, 115; 256/7, 8; chromlum carblde, tungsten carblde, molybdenum 4 1 7 3 14 315; 29 133 4 carbide, niobium carbide, tantalum carbide, titanium 1935 1915 19 I carbide, zirconium carbide, hafnium carbide and iron boride is difused onto the steel. This hard layer has a '5 References Cited smooth working surface and a uniform thickness in the range Of frOm abOUt 8 t0 microns.

2,732,321 1/1956 Gill et a1. 117/130 R 2 Claims, 6 Drawing Figures PATENTED sm o 1974 SHEEI 1 0F 2 1 METALLIC CARD CLOTHING BACKGROUND OF THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS This and further objects, features and advantages of the invention will become more apparent when read the following detailed description of the invention by reference to the accompanying drawings. In the drawmgs:

FIG. 1 is a partial perspective view of a conventional metallic wire;

'FIG. 2 is a cross-section of the-metallic wire shown in FIG. 1, being taken along the section line IIII shown therein;

FIG. 3 is a perspective view of a metallic wire according to the presentinvention which is shown by way of example in the. stage of manufacturing stage attached on a dip treatment jig; and V FIGS. 4-6 represent several photomicrographs manually reproduced of a part of the working part of the metallic wireaccording to this invention, the magnification being 200 times, and more specifically, FIG. 4 showing a covering layer of chromium carbide; FIG. 5 that of vanadium carbide and FIG. 6 that of iron boride.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In the following, and in advance of setting forth of the improved metallic wire, a comparative conventional one will be preliminarily described by reference to FIGS. 1 and 2, for better understanding of the present invention. H

In these figures, numeral 1 denotes a conventional representative metallic wire which is provided with a saw-tooth working part denoted with numeral 11. As is commonly known, these kinds of metallic wires'are used on various spinning machinery, so as to cooperate, by way of examples, with the cylinders, rollers of opener and carding machines or with combing rollers of open end spinning machines. The saw-tooth of the metallic wire serves for combing the fibers and for opening the fiber mass.

Therefore, the saw tooth-shaped working portion 11 of the metallic wire must have a highly wear-resistant and smooth surface.

The reason for this is as follows:

In the operating period, the saw-tooth working portion 11 of the metallic wire is kept in sliding contact with the fibers being treated while they are flowing at a high speed, thereby said portion is subjected to severe wearing. Especially, in the treatment of synthetic fibers such as polyester fibers, this disadvantageous tendency is highly remarkable and recessed strips will develop on the working surfaces, resulting in frequent unintentional cuttingoff of the fibers. In addition, the fibers may frequently entangle around the saw-teeth, which invites frequently insufficient fiber openings. Uneven thickness of the product yarns and increased development of naps thereon will thus be unavoidably and disadvantageously invited.

It will thus be seen that the degree of the antiwearing property at least of the working portions of metallic wires plays an important role in the manufacture of spun fiber products, especially yarns. On account of the frequent and severe sliding contact of the saw-toothed working portion of metallic wire with the fiber, it should have a highly smooth working surfaces.

Worn and striped metallic wires must be replaced by a new one. In consideration of the high productive efficiency in the manufacture of yarns, especially in recent.

years, and most preferably in the case of the continuous operation of the spinning machinery, there is a requisite and urgent demand for metallic wires with highly antiwearing working surfaces among those skilled in the art.

As a conventional measure for improving wearing performance, the metallic wire is generally prepared from steel which is quench hardened, especially at its working regions. However, it was found that in the case of treatment of synthetic fibers, such metallic wires show a relatively low resistance to wear, thus the durable life thereof is very short.

A representative counter measure against excessive wearing of the metallic wire is to spray a molten hard material on the working surface thereof. Although substantial improvement in the antiwearing characteristics can be obtained by the above measure over that of the quench hardening, an appreciable toughening of the working surfacethus treated may generally be encountered. Moreover, in this case, special means are necessary for carrying out this kind of surface-improving technique, which invited, naturally an increased cost of necessary investment.

In consideration of the aforementioned conventional defective measures and upon conducting various and numerous experiments for the formation of a very hard and durable protecting layer on the working surfaces of metallic wire, it has now been found that when at least a compound selected from the group consisting of vanadium carbide, chromium carbide, tungsten carbide, molibdenum carbide, niobium carbide, tantalum carbide, titanium carbide, zirconium carbide, hafnium carbide and iron boride is formed at least on the working surfaces of a metallic wire made of steel, as a protecting layer thereof by means of diffusion treatment, a superior metallic wire can be provided. In' this way a highly intimate and strong bond between the protecting layer and the mother material or steel is attained and the layer represents a highly unified and is of even thickness, in addition to highly a highly smooth surface.

The aforementioned kinds of carbides of boride represent a high degree of hardness and have highly durable antiwearing performance, thus providing the aforementioned desired characteristics for the metallic wire to a satisfying degree. According to the results of experiments, the metallic wire improved in the aforementioned way represents high superiority in surface hardness as -well as antiwearing performance and surface smoothness over those prepared by the conventional hardening and surface-improving techniques including the electroplating process.

The reason why the diffusion treatment process is employed in the practice of the invention is as follows.

When a person tries to prepare a similar hard protecting layer by spraying, it results in the formation of an appreciably roughened surface which must necessarily be subjected to a finish grinding step. These roughened surfaces will substantially disturb a smooth flow of the fibers under treatment and frequent breakage of the yarns may be encountered.

When the person transfers a hard metal alloy to the mother steel of the metallic wire with the help of electric discharge energy i.e. through spark hardening, a more roughened surface layer may be observed than the case of the spray process.

When relying upon an evaporative deposition process, it is highly difficult to form an even thickness layer of the hard material over the whole working surfaces of the metallic wire of an appreciably complicated configuration.

When relied upon the conventional electroplating process, an uneven layer will similarly develop.

It should be mentioned at this stage of disclosure that the protecting layer formed by reliance of any one of r the aforementioned known processes, the bonding of the protecting layer with the mother steel is primarily of a mechanical nature and thus of appreciably inferior nature.

By employing, however, the diffusion method as proposed by the present invention, the carbideor borideforming elements diffuse into the mother steel, resulting in the aforementioned formation of carbideor boride-layer on the surface of the mother steel. This layer represents a very smooth surface. In addition, such layer is very even and of uniform thickness, in spite of the substantially complicated configuration of the working portion of metallic wire.

The bonding of the protecting layer with the mother steel is metallurgical, caused by the mutual diffusion and characterized by its very strong nature.

It will be seen from the foregoing that the metallic wire according to this invention has a protecting layer having a highly smooth and wear-resistant surface, an even and uniform thickness, and a metallurgical bond between the layer and the mother steel.

Since it is experienced that the inherent function of the metallic wire is highly influenced by the configuration of the saw-toothed working part thereof, the metallic wire according to this invention is highly advantageous. With uneven thickness of the protecting layer, a corresponding variation of the configuration, especially at the working portion, will result which means a substantial drawback in the art. The employment of an additional and separate finish or correction grinding after formation of the protecting layer on the metallic wire with a rather complicated configuration will consume a substantial amount of additional labor and invite substantial technical difficulty. When, however, relying upon the novel teaching suggested by the present invention, using the diffusion treatment, the sawtoothed working portion of the metallic wire has the desired precise configuration, thus providing the desired optimum function and a highly improved durability.

The diffusion treatment in the above sense can be carried out in any one of the following several ways.

In the case of the molten salt process, the mother steel of the metallic wire previously shaped to its final shape is held in the dipped manner for a certain predetermined time period within a molten salt mixture comprising a material containing the desired element such as vanadium or the like necessary for the formation of said protecting layer, and borax, fluoride and/or chloride.

In the case of the electrolytic process, the immersing step for the metallic wire is carried out by use of the electrical current so as to invite an electrolytic action between the mother steel and the molten bath materials.

In the case of the pack cementation, the mother steel is embedded in a powdery mass containing the aforementioned several materials including the layerforming basic element or coated with a paste-like mass comprising said materials, and then held at an elevated temperature.

In the case of the gaseous phase process, the mother steel is heated in a mixed gas atmosphere comprising a gaseous halide such as fluoride or chloride of the carbideor boride-forming elements, and a carrier gas such as hydrogen, argon or the like.

In the progress of the aforementioned diffusion treatment, the carbide may form by reaction of vanadium or like element with carbon in the steel during the diffusing step. When necessary, however, an additional amount of carbon, enough necessary for the sufficient formation of the carbide, can be supplied to the diffusion treatment material(s). It is generally sufficient to form the carbide or boride coating substantially exclusively upon the working portion of the metallic wire under normal conditions.

Several preferred examples will now be given for a better understanding of the nature and function of the metallic wire according to this invention.

EXAMPLE 1 A combing wire, as shown at l in FIG. 1 was prepared by proper machining from a carbon steel stock containing 0.4% carbon, so as to have a saw-tooth shaped working portion as shown at 11 therein and adapted for use on a conventional open end spinning machine and immersed in a molten salt bath consisting of a mixture of borax and iron-chromium alloy. In this way, a protecting layer consisting of chromium carbide (Cr C was formed on the surface of the combing wire.

More specifically, the wire 1, having a length of 2 meters was coiled around a jig 2 having a cross section of a cross, with the both ends of said wire fixedly attached to metallic positioners 3 which were attached in turn fixedly on the jig.

This jig and wire assembly, shown in FIG. 3, was immersed for 16 hours in a molten salt bath, held at 950C, consisting of 5.95 kg of borax and 1.05 kg of ferro-chromium alloy (chromium content: 67%). The combing wire was then taken out from the molten salt bath and cooled down in the open atmosphere.

The removed assembly was washed with clean water and the wire 1 was removed from the jig 2.

A manually reproduced photomicrograph (magnification being 200 times) of a part of the cross-section taken substantially along the section line IIII is shown in FIG. 4, representing a part of the working portion of the wire. An overall cross-section is shown in FIG. 2.

A whitish peripheral layer appearing in FIG. 4, represents the protecting layer, having a smooth surface and a substantially even thickness of about 10 microns tron microscope taken from the protecting layer andthe marginal portion existing directly therebelow in the mother steel, and in addition, by taking several X-ray diffraction spectra from the surface of the protecting.

layer, it was found that such layer was mainly composed of Cr C According to these tests and observations, it was determined that there is an intermediate layer between the protecting layer and the mother carbon steel, said intermediate layer being diffused with chromium. The microvickers hardness of the protecting layer was measured to about Hv 2,000 which is an appreciably high value.

The combing wire treated in the above-mentioned way was tested for its wearing resistance.

One of the saw-teeth was kept in sliding engagement with a polyester multifilament, 150 denier, consisting of 30 monofilaments and running at 300 m/min., with a test load of g. t

For comparison, a similar tooth, quench-hardened, I

having a hardness of Hv 900, was tested in the similar way. This hardened tooth was found to have appreciable wear, while the wire according to this invention showed substantially no wear.

Next, the wire was attached to the combing roller of a conventional open end spinning machine and it was found that the wire became defective by forming wearing stripes on the teeth after continued use of about 2,100 hours.

In comparison thereto, the quenched conventional wire became defective upon continued use of about 500 hours by forming wearing stripes on the teeth. After lapse of 550-hour service period, these stripes became appreciable and fibers were entangled. The desired fiber opening operation was substantially disturbed and frequent breakage of the produced yarn was observed. The diameter of the combing roller amounted to about 65 mm. The revolutional speed of the roller was measured at 6,400 r.p.m. The fiber was polyester.

It will be seen from the foregoing that the effective durable life was four times longer than that of the quenched conventional one.

EXAMPLE 2 A similar combing wire was prepared from 1.2%- carbon steel and coiled around the jig shown in FIG. 3. This wire was dipped in a molten salt bath, 950C, for 16 hours, said bath consisting of 5.6 kg of borax and 1.4 kg of ferro-vanadium alloy (including 52% of vanadium). Then, the wire was taken out from the bath, cooled down as before and washed with warm water.

In FIG. 5, a photomicrograph, 200 times magnified and manually reproduced is seen. As shown, the protecting layer was formed, having a smooth surface and substantially uniform thickness which amounted to about 8 microns. According to the electronmicroscopic tests and X-ray diffraction spectrum observations, the protecting cover was found to consist substantially of vanadium carbide. The surface hardness was measured to about Hv 3,000.

From the results of said tests and observations, the region of the mother steel which was in proximity to the protecting layer was found to be slightly diffusioned with vanadium.

Upon subjected the thus coated combing wire to wearing tests as before, substantially no wearing was encountered at the working portion of the wire.

Upon practical use of the wire on an open end spinning machine continuously for about 2,000 hours, the saw-teeth showed no-appreciable wear and substantially maintained its regular fiber-opening function.

EXAMPLE 3 A similar combing wire as before was prepared from a 0.4%-carbon steel and wound on the jig as before.

This wire was then dipped in a molten salt bath, 900C, for 1 hour, said bath consisting substantially of 4.2. kg of borax and 2.8 kg of boron carbide (8 C). Then, the wire was taken out from the bath, and cooled down in the open atmosphere, whereupon it was washed with warm water as before.

Upon tested and observed as before, a photomicrograph was taken as shown in FIG. 6 which was, however, manually reproduced by virture of printing difficulties. The wire teeth were covered with a protecting layer, about 20 microns thick. This layer was analysed to consist substantially of borides (FeB and Fe B). The thickness of this protecting layer was substantially uniform and the surface condition was very smooth. The hardness of the protecting layer was measured to Hv 1,700.

According to the results of said tests and observations, the region of the mother material in proximity to the protecting layer was observed as diffused with boron.

This wire was then subjected to wear-resistant tests as before, and no wearing on the teeth was observed. Upon practical use of the wire on a conventional spinning machine as before, apparent wear and defective fiber-opening function was observed only after about 2,300 hours of practical use.

For reference, a metallic wire made of steel was sprayed with a mixture of 8% cobalt and the remainder of tungsten carbide, or a further mixture of 25% tungsten carbide, 7% nickel and remainder tungstenchromium carbide on the sawtooth working portion of the metallic wire to form a protecting layer, which wire was then used in practice on an open end spinning machine. These wires were durable for about 3,000 hours of practical use. In comparison with the inventive metallic wires described hereinbefore, the wire above prepared in accordance with the prior technique invited substantial yarn breakage and development of scum, resulting in a substantially poor yarn quality. This drawback may be attributable to rough surface conditions of the protecting layer.

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY OR PRIVI- .LEGE IS CLAIMED ARE AS FOLLOWS:

1. A metallic card clothing wire made of steel, having a base portion and a toothed working portion; at least said tooth working portion having a hard layer diffused onto the steel selected from a group consisting of vanadium carbide, niobium carbide and tantalum carbide; and said diffused hard layer having a smooth working surface and a uniform thickness so as to be extremely wear-resistant when combing synthetics.

2. The metallic card clothing wire as claimed in claim 1 wherein said diffused hard layer has a thickness of about 8 microns. 

2. The metallic card clothing wire as claimed in claim 1 wherein said diffused hard layer has a thickness of about 8 microns. 